Transplantation experiments with the fat body of Calliphora: A morphometric study of induced ultrastructural changes

Summary Transplantation of fragments of the anterior fat body lobe of 4 day old feeding stage larvae into one day older hosts, which are at the end of feeding, leads to precocious induction of ultrastructural changes in the transplanted cells of the fat body. These changes include alterations in the mean relative and absolute areas of mitochondria, protein granules, lipid droplets and vacuoles. The extent of intracellular changes induced in the transplants depends on the physiological condition of the host. This confirms that alterations in the internal environment at termination of feeding induce premetamorphic changes in cells of the fat body.     

羊膜及羊膜匀浆液在眼科学中应用的研究进展

羊膜应用于医学已有一个多世纪,应用于眼科也有70余年的历史。因种种原因,在很长一段时间里,对羊膜的研究停滞不前,但随着生物医学技术和其它相关技术的发展,羊膜的解剖结构及生物学特性研究得越来越深入。而随着羊膜的解剖和生物学特性日益明确,羊膜在医学和组织工程学中的应用也越来越广泛,并且应用前景广阔。近年来,由于羊膜的诸多解剖和生物学特性符合眼科学发展的需要,羊膜在眼科中的应用也日益广泛,并取得了良好的临床效果。羊膜的研磨提取液-羊膜匀浆液保留了羊膜中的有效生物成分,在治疗眼部疾病方面也取得了一定的进展。国内外关于羊膜及羊膜匀浆的研究文献有很多,为了更深入了解羊膜的特性及其在眼科疾病治疗方面的优势,该文将对羊膜的应用历史、羊膜及羊膜匀浆液的制备及保存、生物学特性及其在眼科学中的应用作一综述。     

细胞重编程和移植技术用于帕金森病治疗的研究进展

帕金森病(Parkinson disease,PD)是一种复杂的中枢神经系统退行性疾病,主要病理特征为黑质致密部多巴胺神经元的进行性丧失.目前PD主要治疗手段包括药物和手术.但药物存在神经保护活性不足、缺乏对因治疗、晚期无药可用等问题,手术治疗风险较大.近年来,细胞重编程技术取得突破性进展,由重编程产生的诱导多能干细胞(induced pluripotent stem cells,iPSCs)、诱导多巴胺神经元(induced dopamine neurons,iDNs)和诱导神经干细胞(induced neural stem cells,i NSCs)可用于治疗PD.移植iPSCs分化而来的多巴胺能神经元、iDNs和iNSCs至相应脑区,可起到神经替代与修复作用,有效治疗PD.本文重点介绍细胞重编程的机制,总结iPSCs、iDNs和iNSCs治疗PD的优缺点,并阐述尚存在的挑战,探讨可能的解决方案.     

Next generation organoids for biomedical research and applications

Organoids are in vitro cultures of miniature fetal or adult organ-like structures. Their potentials for use in tissue and organ replacement, disease modeling, toxicology studies, and drug discovery are tremendous. Currently, major challenges facing human organoid technology include (i) improving the range of cellular heterogeneity for a particular organoid system, (ii) mimicking the native micro- and matrix-environment encountered by cells within organoids, and (iii) developing robust protocols for the in vitro maturation of organoids that remain mostly fetal-like in cultures. To tackle these challenges, we advocate the principle of reverse engineering that replicates the inner workings of in vivo systems with the goal of achieving functionality and maturation of the resulting organoid structures with the input of minimal intrinsic (cellular) and environmental (matrix and niche) constituents. Here, we present an overview of organoid technology development in several systems that employ cell materials derived from fetal and adult tissues and pluripotent stem cell cultures. We focus on key studies that exploit the self-organizing property of embryonic progenitors and the role of designer matrices and cell-free scaffolds in assisting organoid formation. We further explore the relationship between adult stem cells, niche factors, and other current developments that aim to enhance robust organoid maturation. From these works, we propose a standardized pipeline for the development of future protocols that would help generate more physiologically relevant human organoids for various biomedical applications.     

Trichinella spiralis: inhibition of sheep hemagglutinins in mice

One hundred and twenty-four mice were injected intraperitoneally with sheep red blood cells. The mice had been previously either orally inoculated with T. spiralis (16 mice), or injected intraperitoneally during 7 consecutive days with normal saline (12 mice), normal mouse serum (6 mice), or infected mouse serum (6 mice), normal rabbit serum (6 mice), sera from lightly (36 mice) or heavily infected rabbits (36 mice), and rabbit anti-lymphocyte serum (6 mice). The homologous serum clearly demonstrated an immunosuppressive effect on the production of sheep hemagglutinins; however, it was impossible to conclude that heterologous serum has such an activity since the normal rabbit serum used as control demonstrated the same activity. The inhibition of hemagglutinin production has also been observed in mice infected with T. spiralis. The presence of a suppressive agent released by the parasite or antigenic competition is discussed as the possible mediator of immunological unresponsiveness.     

Current applications of adipose-derived stem cells and their future perspectives简

Adult stem cells have a great potential to treat various diseases. For these cell-based therapies, adipose-derived stem cells (ADSCs) are one of the most promising stem cell types, including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). ESCs and iPSCs have taken center stage due to their pluripotency. However, ESCs and iPSCs have limitations in ethical issues and in identification of characteristics, respectively. Unlike ESCs and iPSCs, ADSCs do not have such limitations and are not only easily obtained but also uniquely expandable. ADSCs can differentiate into adipocytes, osteoblasts, chondrocytes, myocytes and neurons under specific differentiation conditions, and these kinds of differentiation potential of ADSCs could be applied in regenerative medicine e.g., skin reconstruction, bone and cartilage formation, etc. In this review, the current status of ADSC isolation, differentiation and their therapeutic applications are discussed.     

Energy charge restoration, mitochondrial protection and reversal of preservation induced liver injury by hypothermic oxygenation prior to reperfusion

Background

We investigated the benefit of two different techniques for resuscitating marginally preserved liver grafts, unexpectedly subjected to long storage times.

Methods

Rat livers were cold-stored for 22 h (CS22). Some grafts were subsequently subjected to 90 min of hypothermic reconditioning by venous systemic oxygen persufflation (VSOP) or oxygenated hypothermic machine perfusion (HMP). Livers stored for only 6 h (CS6) served as reference. Viability of the livers was assessed thereafter by warm reperfusion in vitro.

Results

VSOP and HMP significantly increased endischemic tissue energy charge, and abrogated cellular enzyme loss upon reperfusion even significantly below control values. Ammonia clearance and bile production were more than 3-fold improved to similar values as CS6. Hypothermic reconditioning by both techniques induced mitochondrial chaperone expression (HSP70 family) and significantly improved early resumption of oxygen utilisation upon reperfusion.

Conclusion

Viability of long preserved liver grafts can be augmented by transient hypothermic reconditioning using either machine perfusion or gaseous oxygen persufflation, both preventing initial mitochondrial dysfunction and subsequent tissue injury.     

Origin of pancreatic precursors in the chick embryo and the mechanism of endoderm regionalization

To study the developmental origin of the pancreas we used DiI crystals to mark regions of the early chick endoderm: this allowed correlations to be established between specific endoderm sites and the positions of their descendants. Endodermal precursor cells for the stomach, pancreas and intestine were found to segregate immediately after completion of gastrulation. Transplantation experiments showed that region-specific endodermal fates are determined sequentially in the order stomach, intestine, and then pancreas. Non-pancreatic endoderm transplanted to the stomach region generated ectopic pancreas expressing both insulin and glucagon. These results imply that a pancreas-inducing signal is emitted from somitic mesoderm underlying the pre-pancreatic region, and this extends rostrally beyond the stomach endoderm region at the early somite stage. Transplantation experiments revealed that the endoderm responding to these pancreatic-inducing signals lies within the pre-pancreatic region and extends caudally beyond the region of the intestinal endoderm. The results indicate that pancreatic fate is determined in the area of overlap between these two regions.     

造血干细胞动员与移植治疗脑梗死的对比研究

目的对比造血干细胞（HSCs）内源性动员与外源性移植治疗大鼠脑梗死疗效。方法根据Longa线栓法建立大鼠大脑中动脉闭塞模型（MCAO）,7d后随机分成四组：A组（HSCs移植组）、B组（PBS组）、C组（HSCs动员组）、D组（对照组）。A组定向植入1×10^6个HSCs;B组植入PBS液;C组皮下注射重组人粒细胞集落刺激因子（rhG—CSF）10ug／kg／d,连用5d;D组不进行干预。移植前、后进行NSS评分;经免疫组化观察CD34、Nestin、VEGF、vWF阳性细胞的分布情况;TCC染色观察梗死体积的变化。结果第1周A组梗死侧半球CD34、Nestin、VEGF、vWF细胞高于其它3组（P〈0．01）,C组Nestin、VEGF、vWF细胞高于B组和D组（P〈0．05）;第4周各组未见CD34细胞,A、C两组Nestin、VEGF细胞减少,vWF细胞增多（P〈0．05）;A组Nestin、VEGF、vWF细胞高于其它3组（P〈0．01）,B、C、D组Nestin、VEGF细胞的差异无统计学意义,C组vWF细胞高于B组、D组（P〈0．05）。A组神经功能改善最显著,C组次之,B、D组间差异无统计学意义（P〉0．05）。A组梗死体积明显缩小（P〈0．01）,B、C、D组间无差异（P〉0．05）。结论HSCs外源性移植对脑梗死后袄的大鼠治疗效果好于动员。     

Organ and tissue safety workshop 2007: advances and challenges

A workshop in June 2005 (“Preventing Organ and Tissue Allograft-Transmitted Infection: Priorities for Public Health Intervention”) identified gaps in organ and tissue safety in the US. Participants developed a series of allograft safety initiatives. “The Organ and Tissue Safety Workshop 2007: Advances and Challenges” assessed progress and identified priorities for future interventions. Awareness of the challenges of allograft-associated disease transmission has increased. The Transplantation Transmission Sentinel Network will enhance communication surrounding allograft-associated disease transmission. Other patient safety initiatives have focused on adverse event reporting and microbiologic screening technologies. Despite progress, improved recognition and prevention of donor-derived transmission events is needed. This requires systems integration across the organ and tissue transplantation communities including organ procurement organizations, eye and tissue banks, and transplant infectious disease experts. Commitment of resources and improved coordination of efforts are required to develop essential tools to enhance safety for allograft recipients.